Cell transport is the movement of items into and out of the cell through the cell's membrane. This movement is done with a variety of proteins to facilitate the action.
Cell transport may take place either as passive or active transport. Passive transport does not involve the use of additional energy. It moves items from a higher area of substance concentration to a lower area of substance concentration. Passive transport may also be referred to as diffusion. Active transport also moves substances from a region of higher to lower concentration. However, active transport requires the use of energy in some form. Often, this energy is in the form of ATP or ADP. Both organic and inorganic molecules move into and out of the cell.
Two examples of passive transport are facilitated diffusion and osmosis. Facilitated diffusion involves the use of a protein to move an item across the cell membrane. An example of this type of transport is moving glucose into the cell. To remove glucose from the cell, a more active form of transport using more energy is required. Osmosis, a second type of passive transport, is a process that involves moving water across a membrane. Its purpose is to achieve an equal concentration of ions on both sides of the membrane.